From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Carburetter and induction modifications for the 20.HP car to increase power.
| Identifier | WestWitteringFiles\N\2July1925-September1925\ Scan65 | |
| Date | 1st September 1925 | |
| R.R. 235A (100 T) (S.H. 159, 11-8-20) G.{Mr Griffiths - Chief Accountant / Mr Gnapp} 2800 ORIGINAL TO HS.{Lord Ernest Hives - Chair} FROM R.{Sir Henry Royce} Copy to C.L. D.T. 20.HP. CAR. X5080 V5770 X5070 We have some modifications instructed for the carburetter which we hope will give more power, if we take the trouble to make the induction passage through the cyls. into a venturi, namely, the smaller bore between the cyls. We should then ask you to fit the double exhaust pipe and cutout, so as to be in line with the 40/50., to do away with the hot spot, and find an aluminium induction pipe that would naturally give good distribution when cold, and perfect distribution when the water round the venturi is at the usual temperature of about 70°C. We are also hoping that you will examine the effect of slow running and noise in the induction pipe, due to over-lapping valves, (but we have the impression that any early opening of the induction pipe will cause a fluttering noise in the carburetter at full throttle;) we want someone to work very hard trying to get a little more power out of this engine, preferably all through the speeds, but if we get more power at any speed without suffering some disadvantages, we shall be grateful, because, delightful as this smaller car is, we are often told that in power and speed it is not up to the behaviour of other peoples' 20HP. models, especially referring to the Lanchester and Sunbeam, probably our worst competitors. R.{Sir Henry Royce} RECEIVED | ||